Background and Objectives: Immunological dysfunction is responsible for increased morbidity and mortality due to recurrent infections and hospital admission in Type 2 DM. There are limited studies and markers for the assessment of immunological dysfunction and serum ADA is one of the marker of immunological dysfunction as proven in several studies. The present study is an attempt to correlate ADA as a marker of altered immune function in diabetes mellitus with respect to glycemic control as assessed by HbA1C